The next year Le Gallienne sailed for New York, and then on to Arizona and California where she performed in several theatre productions. After travelling in Europe for a period of time, she returned to New York and became a Broadway star in several plays including Arthur Richman's Not So Long Ago (1920) and Ferenc Molnár's Liliom (1921).

Disillusioned by the state of commercial theatre in the 1920s, Le Gallienne founded the Civic Repertory Theatre in the former Fourteenth Street Theatre in Manhattan, New York. She was backed by the financial support of one of her lovers, Alice DeLamar, a wealthy Colorado gold mine heiress, whose support was instrumental in the success of the repertory theatre movement in the U.S.. In 1928 she earned a great success with her performance in Ibsen's Hedda Gabler. As head of the Civic Repertory Theatre, she is known to have rejected the admission of Bette Davis, whose attitude she described as "insincere" and "frivolous". The Civic Rep disbanded at the height of the Depression in 1934.[2]

In 1918, while in Hollywood, she began an affair with the great actress Alla Nazimova, who was at her height of fame, and who at that time wielded much power in the acting community. The affair ended reportedly due to Nazimova's jealousy. Nonetheless, Nazimova liked Le Gallienne greatly, and assisted in her being introduced to many influential people of the day. It was Nazimova who coined the phrase "sewing circles", to describe the intricate and secret lesbian relationships lived by many actresses of the day. Le Gallienne was also involved for some time with actresses Tallulah Bankhead, Beatrice Lillie and Laurette Taylor during that time. Her only known heterosexual affair was with actor Basil Rathbone.[4]

In 1920, she became involved with poet, novelist and playwright Mercedes de Acosta about whom she was passionate for several years.[5] She and de Acosta began their romance shortly after de Acosta's marriage to Abram Poole which strained their relationship. Still, they vacationed and travelled together often, at times visiting the salon of famed writer and socialite Natalie Barney.[3] De Acosta wrote two plays for Eva during that time, Sandro Botticelli and Jehanne de Arc. Neither was successful. They ended their relationship after five years.[6]

In 1960, when de Acosta was seriously ill with a brain tumour and in need of money, she published her memoir, Here Lies the Heart. The reviews were positive and many close friends praised the book.[7] But its allusions to homosexuality resulted in the severance of several friendships who felt she had betrayed their sexuality. Le Gallienne in particular was furious, denouncing de Acosta as a liar and stating that she invented the stories for fame. This assessment is inaccurate, however, since many of her affairs, including that with Le Gallienne, are confirmed in personal correspondence.[8]

By early 1927, Le Gallienne was involved with married actress Josephine Hutchinson. Hutchinson's husband started divorce proceedings and named Le Gallienne in the divorce proceedings as "co-respondent". The press began accusations that named Josephine Hutchinson as a "shadow actress", which at the time meant lesbian. Five months later, Le Gallienne performed in the daring play about Emily Dickinson, titled Alison's House. The play won a Pulitzer Prize.[3]

For a time after the Hutchinson scandal, Le Gallienne drank heavily. According to biographer Robert Schanke, Le Gallienne's anxiety over being lesbian haunted her terribly during this time. One cold winter's night, drunk, she wandered over to a female neighbour's house. During the conversation that followed, she told her neighbour "If you have any thoughts about being a lesbian, don't do it. Your life will be nothing but tragedy."[3]

Another biographer, Helen Sheehy, has rejected Schanke's portrait of the actress as a self-hating lesbian. Sheehy quotes Le Gallienne's words of advice to her close friend May Sarton, who was also a lesbian: "People hate what they don't understand and try to destroy it. Only try to keep yourself clear and don't allow that destructive force to spoil something that to you is simple, natural, and beautiful." Similarly, Le Gallienne told her heterosexual friend, Eloise Armen, that love between women was "the most beautiful thing in the world."

Eva Le Gallienne starred as Peter Pan in a revival that opened on 6 November 1928, and presented the lead character full of elan and boyish charm. The flying effects were superbly designed, and for the first time Peter flew out over the heads of the audience. The critics loved "LeG", as she became known, and more than a few compared her favourably with the great actress Maude Adams, who had originated the role. The Civic Repertory Theatre presented Peter Pan a total of 129 times.

In late 1929, just after the great stock market crash, Le Gallienne was on the cover of TIME. During the Great Depression that followed, she was offered directorship of the National Theatre Division of the Works Progress Administration by President Franklin D. Roosevelt. She declined on the grounds that she preferred working with "true talent" rather than nurturing jobs for struggling actors and actresses.[3] She was instrumental in the early career of Uta Hagen, whom she cast as Ophelia opposite her own portrayal of Shakespeare's Prince Hamlet.